Bernard L. Madoff pleaded guilty Thursday to all the charges against him and expressed remorse for a vast Ponzi scheme that bilked investors out of billions of dollars....

In answering questions about how he sustained a 20-year fraud whose collapse erased as much as $65 billion that his customers thought they had in their accounts, Mr. Madoff said, “I believed it would end shortly and I would be able to extricate myself and my clients from the scheme.”

“As the years went by I realized that my arrest and this day would inevitably come,” Mr. Madoff said. “I cannot adequately express how sorry I am for what I have done.” Although Mr. Madoff admitted to operating what he called “a Ponzi scheme through the investment advisory side of my business,” he said all other aspects of his enterprise, operated by his sons and brother, were legitimate, profitable and successful.